DESCRIPTION: (Applicant's Abstract) The majority of extant studies of the long-term consequences of adolescent drug abuse have been based on random samples drawn from the general population. Because these studies have low rates of clinical-level drug abusing adolescents, little is known about the long-term consequences of adolescent drug abuse. This revision of a continuation study of DA05104 proposes to focus on the description of the long-term outcomes, including drug abuse, patterns of relapse, and level of functioning in a young adult sample with a DSM-IV lifetime diagnosis of at least one substance use disorder. This target group will consist of 195 participants, aged 20-23. A control sample of normal young adults (n-130) matched for age, ethnicity, and educational status will provide a comparison group. The following specific aims will be addressed: Aim 1: To describe the long-term (4 years) drug involvement severity and other psychosocial outcomes, including the comparison of the target (clinical) group and a control (normal) group. Such descriptions of a clinical drug-abusing adolescent sample, supplemented by a comparison to a matched control group, will provide invaluable contributions to the field regarding questions of the course of drug use and other problem areas from adolescence to young adulthood. Aim 2: To examine the relationship of prior drug involvement severity and psychosocial functioning to young adult outcomes in these domains. It is hypothesized that greater prior drug abuse and psychosocial risk will be associated with poorer psychosocial and health functioning (e.g., less educational attainment and more interpersonal problems), and more instances of continued drug abuse and co-morbid psychiatric disorders. Aim 3: To examine the relationship of prior drug involvement and psychosocial risk and developmental outcomes. It is hypothesized that greater prior drug use and psychosocial risk will be associated with poorer results on the developmental outcome measures. Aim 4: To evaluate the appropriateness of a model of post-treatment outcome adapted from the adult literature and alcohol adolescent literature to explain outcome patterns at year-1 and year-4. Aim 5: To describe the antecedents of drug use lapse and relapse in the young adult target sample at year 4.